During user-initiated enrollment, Mac users hit the "...you need to install the MDM profile for your organization" screen. When they click Continue, the site chugs for about 5-10 seconds and just goes to a screen that says "null" with an indeterminate progress spinner. No MDM profile or QuickAdd package is downloaded.
This started randomly happening a couple of weeks ago and seems to work for some machines and not others (mostly not). Most machines are on 10.13.6. We are cloud-hosted and are skipping the certificate installation step, though I have tried it with this step enabled but see no difference.